Competitive pressures have increased the reliability and durability requirements for heavy duty diesel engines. In addition, performance and exhaust emission improvements have increased the thermal and mechanical loading on critical heavy duty diesel engine components. In particular, the loading on piston rings and thus cylinder liners has increased causing excessive wear.
Conventional cylinder liners are mounted in an engine cylinder to provide a smooth, durable surface for sealingly cooperating with piston rings to create a gaseous seal between the combustion chamber and the engine crankcase. Excessive loading over time results in undesirably rapid wear of the liner disadvantageously causing blow-by problems and requiring liner replacement thereby unnecessarily increasing costs. Conventionally, the wear resistance of liners has been improved by using a base material for forming the entire liner which has high wear resistance qualities. However, this strategy may sacrifice other important mechanical properties and/or significantly increase costs. Another possible improvement is to apply a wear resistant coating to the inner surface of the liner base material. However, this method significantly increases the costs of the manufacturing process due to the coating and the process of applying the coating.
U.S. Pat. Nos. 982,739 to Moore and 1,836,798 to Hefti each disclose cylinder liners formed of separate cylindrical parts which abut and engage in end-to-end relationship. However, the separate liner parts are not welded together. Moreover, these references no where suggest forming liner parts of different materials. U.S. Pat. No. 1,512,570 discloses a similar cylinder liner arrangement.
U.S. Pat. No. 3,452,914 to Oberle et al., Russian Patent No. 797,859 and German Patent No. 2559129 all disclose hollow cylindrical assemblies formed by end-to-end friction welding of cylindrical segments. However, the cylindrical assemblies are not cylinder liners.
U.K. Patent No. 2,091,153 discloses friction welding of workpieces formed of differing materials.
Consequently, there is a need for a durable cylinder liner for an internal combustion engine capable of effectively resisting wear and thermal distortion while maintaining structural integrity and a method for manufacturing the cylinder liner which minimizes the costs.